NY · GEOID 36109

Tompkins County area

Tompkins County, New York covers 491.5 square miles: 474.7 square miles of land and 16.9 square miles of water.

Official Census measurements2026 Gazetteer · retrieved September 27, 2026
Land area474.7 mi²
Water area16.9 mi²
Total area491.5 mi²
National land rank#2170

County outline

Generalized outline of Tompkins County, New York
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where Tompkins County is located

Tompkins County highlighted on a map of all U.S. county equivalents. About the maps

Area breakdown

Land accounts for 96.6% of Tompkins County’s measured area and water for 3.4%. Its combined area converts to 1,273.1 square kilometers or approximately 314,591 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land474.651,229.338303,776
Water16.89843.76610,814.7
Total491.5481,273.103314,590.7

How Tompkins County compares

By original Census land area, Tompkins County ranks #46 of 62 in New York and #2170 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.726 times the New York county-equivalent median of 653.7 square miles. It accounts for 1% of the combined county land area in the state.

See the complete New York ranking · What counts as a county equivalent?

What stands out about Tompkins County?

Tompkins County has more land than 1,052 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Tompkins County474.7 mi²
New York median653.7 mi²
National median604.5 mi²

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Tompkins County at #2,214 nationally by total area, 44 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 3.4%, compared with a national county-equivalent median of 1.2% — 2.3 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Tompkins County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2169Carroll County, Virginia474.7Compare
#2170Tompkins County, New York474.7This county
#2171Cedar County, Missouri474.5Compare

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.

Representative coordinates

The Census internal point is 42.453073, -76.473489. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.

Source and precision

U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 1,229,336,935 m²; AWATER: 43,765,694 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.

Download the official county source ZIP ↗ · Methodology

Common questions

How many acres of land are in Tompkins County?

The land measurement converts to approximately 303,776 acres. Including water, total area is approximately 314,591 acres. One square mile equals 640 acres.

Why might another source show a different area?

Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.

Can this establish a property boundary?

No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.

Cite this county

Download the complete CSV or JSON dataset